海泡石泥浆(Ⅲ)

SEPIOLITE MUD(Ⅲ)

研究了河南和江西产海泡石的造浆率、酸溶性和悬浮体的流变性与稳定性,发现S-6号样品造浆率达50—60m^3/t,大大超过API标准;海泡石悬浮体的流变性服从Brinkman粘度公式,S-5样品的Einstein形状系数K=57;配制海泡石泥浆时可使用常规的降失水剂,降失水剂的册量在复配时可大大降低;海泡石样品的酸溶量达26.6％。在地热、海洋、超深井钻探及配制完井液等方面,海泡石有良好的应用前景。

Six sepiolite samples of vaiious puiity from two mines are evaluated in laboratory. The purest sample, S-6, from Nan-yang, Henan province, gives the highest yield of 50-60m^3/t, a value much greater than the API's standard. The rheologlcal behavior of aqueous sepiolite suspensions is shown to obey to Brinkman's viscosity equation: η_m/η_o=1/(1-x)~K, where η_m and η_o denote the viscosities of suspension at shear rate→∞ and of pure water, x-the volume fraction of sepiolite in suspension and K-a geometric factor, or Einstein's constant. The K-value is determined as 57 for another, the 2nd purest sample, S-5, from Leping, Jiangxi province, with hydrated, polydispersed in size, needle-like particles. Sepiolite muds are characterized by their very high fluid losses, which can, however, be decreased to an acceptible level by using fluid-loss controllers such as CMC-Na, NH_4-PAN, SMP-Ⅱ, and SLSP in larger than normal amount. The necessary amount of fluid-loss controllers is minimized when several such and other chemicals are combined in proper ratios. As determined on a middle-purity sample, S-4, the solubility of sepiolite in acids is more than 25％。